ACALEPH^E. 119 



the upper part of the stem, undergo remarkable metamorphoses after their 

 first appearance as buds until they attain the cubical form, when the group 

 of which it forms a part exactly resembles a young Eudoxia cuboides, QUOY 

 and GAIM. See also GEGENBATJER Zeitsck. fur wiss. Zool. v. s. -292 295. 



Praya LESSON. The two swimming pieces of the colony nearly 

 similar and equal, the covers of the developed groups bounded by 

 round surfaces above and concave beneath. 



Sp. Praya diphyes LESS., KOELLIKEE Die Siphon, von Mess. s. 33 36, Taf. 

 ix. Praya maxima GEGENB. Zeitsck. f. wissensch. Zool. v. s. 301 309, Taf. 

 xvn. fig. i 6. 



The genera Eudoxia, Erscea, Aglaisma ESCHSCH., which have 

 only a single polyp, have been termed monogastric diphyidce by 

 HUXLEY ; but it is almost certain that they are not independent 

 genera. It has been noted above, when treating of Abyla penta- 

 gona, that a single group of this compound diphyes exactly resem- 

 bles Eudoxia cuboides; and here the groups have been seen to 

 detach themselves from the colony both by LEUCKART and by GEGEN- 

 BAUER as indeed the same fact had previously been observed by 

 SARS in his Diphyes truncata. Eudoxia campanulata is believed by 

 LEUCKART to be a group of Diph. acuminata, a new species observed 

 by him at Nice j whilst he has found that Aglaisma pentagonum is 

 not a monogastric diphyes, but an imperfectly developed Abyla pen- 

 tagona, see Zoologisch. Untersuch. s. 54. Erscea is suspected by 

 LEUCKART to be a detached group of Diphyes Koch. WILL. 



Eudoxia (&c.) consists of a cover or bract, a polyp with its pre- 

 hensile organs, a swimming bell (sexual capsule), and usually a 

 smaller bell sprouting from the base of the polyp, which is destined 

 to replace the larger when this has been detached. These parts 

 are all connected by their canals to a portion of common stem.] 



Sp. Erscea pyramidalis WILL, i. 1. fig. 27, &c. ; Comp. LEUCKART Zool. 

 Untersuch. i. s. 43 61, GEGENBAUER Zeitsck. f. wiss. Zool. v. 285 296. 



ORDER II. Ctenophorce, or Beroecea. 



Mouth simple, stomach situated in the axis of the body. Vibra- 

 tile cilia disposed in rows on the surface of the body. Swimming 

 bladders none. 



The Beroecious animals are Acalephs of very different form, 

 which, however, are distinguished from the former order by the 

 absence of swimming bladders [bells] and cartilaginous laminse, as 



